HTTP Paths can change their absolute path based on IAM enablement (#7422)

* ci: announce modifications in the SDK API feed (#7451)

An attribute-only modification is neither an addition nor a break, so it reached the feed as a headline and a link, with the headline claiming new API.

* HTTP Paths can change their absolute path based on IAM enablement

* missed one

* fix failures

* fix crashing test

* address feedback

* unit tests

* slightly more graceful

* fix signing test

* fix other test

* log on invalid path

* throwAssertion is unavailable on watchOS

* fix backend integration tests

* fix import

---------

Co-authored-by: Álvaro Brey <alvaro.brey@revenuecat.com>

Sources/Networking/HTTPClient/HTTPRequestPath.swift

@@ -43,6 +43,9 @@ protocol HTTPRequestPath {
     /// The full relative path for this endpoint.
     var relativePath: String { get }
 
+    /// The full relative path for this endpoint when using IAM tokens.
+    var relativeIAMPath: String { get }
+
     /// The fallback relative path for this endpoint, if any.
     var fallbackRelativePath: String? { get }
 
@@ -62,6 +65,9 @@ protocol HTTPRequestPath {
 
     /// Provides endpoint-specific inputs for response signature verification.
     var responseSignatureContextProvider: ResponseSignatureContextProvider { get }
+
+    /// Whether this path corresponds to an IAM request
+    var isIAMPath: Bool { get }
 }
 
 /// Provides endpoint-specific inputs for backend response signature verification.
@@ -106,6 +112,10 @@ extension HTTPRequestPath {
         return nil
     }
 
+    var relativeIAMPath: String {
+        return self.relativePath
+    }
+
     var usesAPISources: Bool {
         return false
     }
@@ -122,9 +132,14 @@ extension HTTPRequestPath {
         return DefaultResponseSignatureContextProvider()
     }
 
-    var url: URL? { return self.url(proxyURL: nil) }
+    var isIAMPath: Bool {
+        return false
+    }
 
-    func url(proxyURL: URL? = nil, apiSourceURL: URL? = nil, fallbackUrlIndex: Int? = nil) -> URL? {
+    func url(proxyURL: URL? = nil,
+             apiSourceURL: URL? = nil,
+             fallbackUrlIndex: Int? = nil,
+             preferIAMPath: Bool) -> URL? {
         let baseURL: URL
         if let proxyURL {
             // When a Proxy URL is set, we don't support API sources or fallback URLs
@@ -141,7 +156,9 @@ extension HTTPRequestPath {
         } else {
             baseURL = Self.serverHostURL
         }
-        return URL(string: self.relativePath, relativeTo: baseURL)
+
+        let path = preferIAMPath ? self.relativeIAMPath : self.relativePath
+        return URL(string: path, relativeTo: baseURL)
     }
 }
 
@@ -368,7 +385,15 @@ extension HTTPRequest.Path: HTTPRequestPath {
     }
 
     var relativePath: String {
-        return "/v1/\(self.pathComponent)"
+        let component = self.pathComponent
+        if component.hasPrefix("/") { return component }
+        return "/v1/\(component)"
+    }
+
+    var relativeIAMPath: String {
+        let component = self.iamPathComponent
+        if component.hasPrefix("/") { return component }
+        return "/v1/\(component)"
     }
 
     var pathComponent: String {
@@ -434,6 +459,56 @@ extension HTTPRequest.Path: HTTPRequestPath {
         }
     }
 
+    var iamPathComponent: String {
+        // NOTE: cases below that "return self.pathComponent" are indicating
+        // that the corresponding server paths have not yet been migrated to
+        // support access token authorization
+        switch self {
+        case .getCustomerInfo:
+            return "customer"
+        case .getOfferings:
+            return "customer/offerings"
+        case .getIntroEligibility:
+            return "customer/intro_eligibility"
+        case .logIn:
+            assertionFailure("The .login endpoint is not allowed when IAM is enabled")
+            Logger.error("The .login endpoint is not allowed when IAM is enabled")
+            return self.pathComponent
+        case .postAttributionData:
+            return "customer/attribution"
+        case .postOfferForSigning:
+            return "offers"
+        case .postReceiptData:
+            return "receipts"
+        case .postSubscriberAttributes:
+            return "customer/attributes"
+        case .postAdServicesToken:
+            return "customer/adservices_attribution"
+        case .health:
+            return self.pathComponent
+        case .appHealthReport:
+            return "customer/health_report"
+        case .appHealthReportAvailability:
+            return self.pathComponent
+        case .getProductEntitlementMapping:
+            return "product_entitlement_mapping"
+        case .getCustomerCenterConfig:
+            return "customer/customercenter"
+        case .getVirtualCurrencies:
+            return "customer/virtual_currencies"
+        case .postRedeemWebPurchase:
+            return self.pathComponent
+        case .postCreateTicket:
+            return self.pathComponent
+        case .isPurchaseAllowedByRestoreBehavior:
+            return "customer/restore/eligibility"
+        case .rewardVerificationStatus:
+            return self.pathComponent
+        case .remoteConfig:
+            return self.pathComponent
+        }
+    }
+
     var name: String {
         switch self {
         case .getCustomerInfo: